In conventional phase-sensitive optical time domain reflectometry (φ-OTDR), the length of sensing fiber mainly determines the repetition rate of probe light pulses, which limits the extent of detectable frequency range. Moreover, averaging method, which is adopted to enhance the location signal-to-noise-ratio (SNR), further decreases the maximum detectable frequency. This paper demonstrates a distributed vibration sensor with satisfied location SNR and extended frequency response range by using a probe pulse pair with a frequency difference. Experimental results show that this method is able to break the trade-off between the given sensing fiber length and the traditional maximum detectable frequency response of φ-OTDR system.

Date Published: 2 June 2014
PDF: 4 pages
Proc. SPIE 9157, 23rd International Conference on Optical Fibre Sensors, 915761 (2 June 2014); doi: 10.1117/12.2059252

Published in SPIE Proceedings Vol. 9157:
23rd International Conference on Optical Fibre Sensors
José M. López-Higuera; Julian D. C. Jones; Manuel López-Amo; José Luis Santos, Editor(s)